KR20210137680A - Method And Apparatus for Use in Vehicle Brake System - Google Patents

Abstract

A brake system for a vehicle and a control method thereof are disclosed. In accordance with one embodiment of the present invention, the brake system for a vehicle comprises: a main brake system disposed to distribute a braking force to each of wheels of a vehicle; an auxiliary brake system disposed to operate instead of the main brake system upon a malfunction at the main brake system; a signal bus disposed between the main brake system and the auxiliary brake system, and including one or more wired devices formed to transmit a signal indicating the presence or absence of a malfunction between the main brake system and the auxiliary brake system; and a communications unit disposed to transmit and receive information about an operation state to and from the main brake system and the auxiliary brake system. The auxiliary brake system is configured to perform a prior preparation for applying the braking force to each of the wheels of the vehicle when the malfunction signal indicating the presence of the malfunction at the main brake system is detected via the signal bus. In accordance with the present invention, the backup performance of the auxiliary brake system is improved.

Description

Brake system for vehicle and its control method {Method And Apparatus for Use in Vehicle Brake System}

The present disclosure relates to a vehicle braking device and a control method therefor.

The content described in this section merely provides background information for the present disclosure and does not constitute the prior art.

As the development of autonomous driving technology for vehicles is actively developing, issues regarding the driving stability of autonomous vehicles are emerging. The risk of an accident increases if the brake system malfunctions during deceleration or braking while driving an autonomous vehicle.

In order to solve this problem, in the related art, an auxiliary braking device is additionally disposed in the vehicle in case a problem occurs in the braking device. A control unit of the main brake system is generally defined as a main controller unit (MCU), and a control unit of the auxiliary brake unit is generally defined as a redundancy controller unit (RCU). When the MCU recognizes damage to the main brake, it delivers damage information to the RCU through the vehicle's CAN (Controller Area Network) communication. As a result, the RCU takes over control of the vehicle braking system from the MCU and participates in vehicle braking. With such a device and a control method, redundancy in braking performance of a vehicle can be secured.

However, in the prior art, a delay occurs in the backup time of the RCU because the MCU transmits the failure fact to the RCU through CAN communication. CAN communication generally has a communication period of 10 ms. It takes 20 ms for the MCU to notify the RCU of a fault signal and transfer control. That is, during a period of 20 ms, a blank time occurs during which the main brake system does not operate normally and the auxiliary brake system does not transfer control. When the vehicle is traveling at high speed, a time of 20 ms can be fatal to the safety of the occupants.

Accordingly, an object of the present disclosure is to improve backup performance of an auxiliary braking unit in a vehicle braking system.

According to an embodiment of the present disclosure, there is provided a main brake system comprising: a main brake system arranged to distribute a braking force to each wheel of a vehicle; an auxiliary brake system arranged to operate in place of the main engine when a failure occurs in the main engine; a signal bus disposed between the main driving unit and the auxiliary braking unit and including one or more wired devices configured to transmit a signal regarding whether there is a failure between the main driving unit and the auxiliary braking unit; and a communication unit disposed to transmit and receive information regarding the mutual driving state of the main brake unit and the auxiliary brake unit, wherein when the auxiliary brake unit detects a failure signal of the main brake unit through the signal bus, the auxiliary brake unit There is provided a braking device for a vehicle, characterized in that prior preparation for applying a braking force to each wheel is performed.

In addition, according to an embodiment of the present disclosure, the process of detecting, by the control unit of the main moving unit, failure of the main moving unit; When it is determined that a failure has occurred in the main engine unit, the process of transmitting the failure fact to the auxiliary brake unit as a digital signal; The auxiliary braking unit prepares in advance to distribute the braking force to each wheel of the vehicle after receiving the digital signal; transmitting the failure cause information of the main engine to the auxiliary braking unit; Provided is a method of controlling a brake system for a vehicle, including a process in which the auxiliary braking unit receives the control right for the distribution of braking force from the main engine when it is determined that the main engine has lost the braking function.

As described above, according to the present embodiment, in the vehicle braking device and the control method thereof, the auxiliary braking unit uses the signal bus to detect the failure of the main motor unit in a short time, thereby securing the redundancy of the vehicle.

1 is a schematic diagram of a vehicle braking system according to an embodiment of the present disclosure.
2 is a block diagram of a vehicle braking system when the vehicle drives normally according to an exemplary embodiment of the present disclosure.
3 is a block diagram of a brake system for a vehicle when a failure occurs in a main engine according to an embodiment of the present disclosure.
4 is a flowchart illustrating a method of controlling a brake system for a vehicle according to an exemplary embodiment of the present disclosure.

Hereinafter, some embodiments of the present disclosure will be described in detail with reference to exemplary drawings. In adding reference numerals to components in each drawing, it should be noted that the same components are given the same reference numerals as much as possible even though they are indicated in different drawings. In addition, in describing the present disclosure, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present disclosure, the detailed description thereof will be omitted.

In describing the components of the embodiment according to the present disclosure, reference numerals such as first, second, i), ii), a), b) may be used. These signs are only for distinguishing the elements from other elements, and the nature, order, or order of the elements are not limited by the signs. When a part in the specification 'includes' or 'includes' a certain component, it means that other components may be further included, rather than excluding other components, unless explicitly stated to the contrary. .

1 is a schematic diagram of a vehicle braking system according to an embodiment of the present disclosure.

Referring to FIG. 1 , the vehicle braking device includes a master cylinder 110 , a main brake system 120 , an auxiliary brake system 130 , a signal bus 140 , and a communication unit ( communications unit 150 , a first flow path 160 , a second flow path 170 , and all or part of a wheel 180 .

The master cylinder 110 is configured to have at least one chamber to generate hydraulic pressure. The master cylinder 110 is a device for discharging oil by generating hydraulic pressure.

The first flow path 160 is a passage through which oil moves between the master cylinder 110 and the main braking unit 120 and between the master cylinder 110 and the auxiliary braking unit 130 . Unlike FIG. 1 in which the main driving unit 120 and the auxiliary braking unit 130 are arranged in parallel, the main driving unit 120 and the auxiliary braking unit 130 may be connected in series. In this case, the first flow path 160 is disposed only between the master cylinder 110 and the main moving unit 120 .

The second flow path 170 is a passage for distributing hydraulic pressure generated from the main driving unit 120 and the auxiliary braking unit 130 to each wheel 180 of the vehicle. The second flow path 170 shown in FIG. 1 is schematically shown to represent the flow of hydraulic pressure and is not limited to the arrangement method of FIG. 1 .

The signal bus 140 is disposed between the main brake unit 120 and the auxiliary brake unit 130, and includes one or more conductive wires formed to transmit a signal regarding whether or not there is a failure between the main brake unit 120 and the auxiliary brake unit 130. The digital signal includes a first signal (High) and a second signal (Low).

For example, when the main driving unit 120 is operating normally, the main driving unit 120 transmits the first signal to the auxiliary braking unit 130 through the signal bus 140 . When the power of the main braking unit 120 is turned off, the second signal is transmitted to the auxiliary braking unit 130 on the contrary. Using these signals, the main braking unit 120 and the auxiliary braking unit 130 may monitor each other. It takes less than 1 ms to transmit the first signal and the second signal.

The communication unit 150 is disposed to transmit and receive information between the main brake unit 120 and the auxiliary brake unit 130 . The communication unit 150 may use CAN (Controller Area Network) communication. The communication unit 150 serves to transmit/receive signals between the main driving unit 120 and the auxiliary braking unit 130 as well as components requiring in-vehicle communication.

In general, the signal transmission period of the communication unit 150 is about 10 ms. For example, when an abnormal situation occurs in the main driving unit 120 , the main driving unit 120 notifies the auxiliary braking unit 130 of the abnormal situation through CAN communication, and grants the control right of the braking device to the auxiliary braking unit 130 . ), it takes about 20 ms to transmit a transfer signal.

The main driving unit 120 is arranged to distribute a braking force to each wheel of the vehicle. The main motor 120 receives an electrical signal from a brake pedal input and generates hydraulic pressure in the fluid through mechanical operation. The main driving unit 120 may execute functions such as anti-lock brake system (ABS) and electric stability control (ESC), which are safety driving functions, while individually controlling the hydraulic pressure distributed to each wheel.

The main driving unit 120 includes a hydraulic pump, an electric motor arranged to drive the hydraulic pump, a hydraulic module arranged to distribute hydraulic pressure to each wheel of the vehicle, and all of the control unit. or includes some. Since the configuration of the main body 120 is a known technology, a description of each configuration will be omitted. The main braking unit 120 transmits a failure signal to the auxiliary braking unit 130 using the signal bus 140 when an abnormality occurs in any one of the components of the main driving unit 120 such as a hydraulic pump, an electric motor, and a control unit.

(중력가속도의 약 0.65배) 이상의 감속도를 생성한다. 주제동부(120)가

이상의 감속도를 생성할 수 없게 되면 보조제동부(130)가 신속하게 백업(backup)을 해야 한다.Even if it is determined that there is no abnormality in the hydraulic pump, the electric motor, the hydraulic module and the control unit, the main moving unit 120 is a malfunction signal when the main moving unit 120 cannot exert vehicle deceleration more than a preset value. is transmitted to the auxiliary braking unit 130 using the signal bus 140 . For example, the main moving unit 120 having normal performance when decelerating the vehicle

(about 0.65 times the acceleration due to gravity) or more deceleration. The subject east (120)

When the above deceleration cannot be generated, the auxiliary braking unit 130 needs to quickly back up.

Alternatively, even if it is determined that there is no abnormality in the hydraulic pump, the electric motor, the hydraulic module, and the control unit, the main braking unit 120 transmits a failure signal to the auxiliary braking unit 130 when it is determined that the ABS and ESC functions cannot be exerted.

The auxiliary braking unit 130 is disposed to operate in place of the main driving unit 120 when a failure occurs in the main driving unit 120 . The auxiliary braking unit 130 may be arranged in parallel as shown in FIG. 1 , but is not limited thereto, and may also be arranged in series with the main braking unit 120 .

The auxiliary braking unit 130 is not limited to the method of sharing the main driving unit 120 and the second flow path 170 as shown in FIG. 1 , and a separate brake mechanism different from the main driving unit 120 may be disposed. . For example, the auxiliary braking unit 130 may distribute the braking force to each wheel 180 by separately disposing a flow path not connected to the second flow path.

The auxiliary braking unit 130 may have the same function and performance as the main braking unit 120 . The auxiliary braking unit 130 has only a minimal function to maintain safety in case of an emergency such as the main braking unit 120 not working, for example, a function of generating hydraulic pressure only to the front wheel 180a and controlling only the braking of the front wheel 180a. can Alternatively, the auxiliary braking unit 130 may have a function of controlling not only the front wheel 180a of the vehicle but also the braking of the rear wheel 180b.

The main braking unit 120 transmits a signal to the auxiliary braking unit 130 primarily by using the signal bus 140 when a failure occurs. When a failure occurs in any one of the components of the main driving unit 120 in the driving or braking situation of the vehicle, the main driving unit 120 transmits the second signal to the auxiliary braking unit 130 . That is, the first signal is transmitted to the auxiliary braking unit 130 when a failure occurs in the main driving unit 120 and the first signal when the main driving unit 120 operates normally. By using this signal, the auxiliary braking unit 130 may continuously monitor the state of the main braking unit 120 .

When the auxiliary braking unit 130 detects a failure state of the main braking unit 120 through the signal bus 140 , the auxiliary braking unit 130 receives the control right of the braking device from the main braking unit 120 before receiving the control right of each wheel of the vehicle. A prior preparation for applying a braking force to 180 is performed. For example, the preliminary preparation may include generating the hydraulic pressure in advance by the auxiliary braking unit 130 .

After the auxiliary braking unit 130 receives the information on the cause of the failure of the main braking unit 120 through the communication unit 150 , the control right of the braking device of the main braking unit 120 is transferred to the auxiliary braking unit 130 . After the control right is transferred to the auxiliary braking unit 130 , the auxiliary braking unit 130 serves to distribute the braking force to each wheel of the vehicle instead of the main braking unit 120 . That is, the auxiliary braking unit 130 controls the vehicle's braking system.

2 is a block diagram of a vehicle braking system when the vehicle drives normally according to an exemplary embodiment of the present disclosure. 3 is a block diagram of a brake system for a vehicle when a failure occurs in a main engine according to an embodiment of the present disclosure.

Referring to FIG. 2 , when a brake input 200 signal is generated by a driver or an autonomous driving signal, the brake input 200 signal is transmitted to the main brake unit 120 or the auxiliary brake unit 130 . . The main braking unit 120 or the auxiliary braking unit 130 controls each wheel by applying a braking force according to an input signal. In general, when there is no abnormality in the main moving unit 120 , the braking input 200 signal is transmitted only to the main moving unit 120 .

Main motor 120 is a motor (motor, 211), MCP (Motor Current Sensor, 212), MPS (Motor Position Sensor, 213), valve relay (valve relay, 214), hydraulic circuit constituting the main motor 120 (hydraulic circuit, 215), the source voltage (source voltage, 216), when any one of the MCU (Main Controller Unit, 217) is abnormal, the failure signal is transmitted to the auxiliary braking unit 130.

In particular, whether the main moving unit 120 has lost safe driving functions such as ABS and ESC is made by additionally determining whether a WSS (Wheel Slip Sensor) malfunctions.

An abnormality such as a shutdown or a low voltage state may occur in the power supply voltage 216 . When the power supply voltage 216 is shut down, the second signal is automatically transmitted to the auxiliary braking unit 130 , and in the case of a low voltage, the MCU 217 detects this and transmits the second signal to the auxiliary braking unit 130 .

As the failure determination method, the value of the signal base exceeds a preset threshold value, the signal is not received from the sensor for more than a certain time, or by comparing several signal values to only one signal value There may be a method of judging a failure state when an outlier value occurs.

When the auxiliary braking unit 130 receives the failure occurrence signal of the main braking unit 120 from the signal bus 140 , the auxiliary braking unit 130 starts preliminary preparation. When the auxiliary braking unit 130 prepares in advance, the signal of the braking input 200 is not yet transmitted to the auxiliary braking unit 130 .

Referring to FIG. 3 , the auxiliary braking unit 130 receives information on the cause of the failure of the main driving unit 120 through the communication unit 150 , and the control right of the braking device of the main driving unit 120 is transferred to the auxiliary braking unit 130 . Only then is the braking input transmitted to the auxiliary braking unit 130 .

As described above, the vehicle braking system according to the embodiment of the present invention advances the backup preparation time of the auxiliary braking unit 130 by using the signal bus 140 having a faster transmission speed than the communication unit 150 . The improvement of the backup function helps the driver to drive more stably while the vehicle is driving at high speed, and in particular, has the effect of increasing the stability of the autonomous vehicle.

4 is a flowchart illustrating a method of controlling a brake system for a vehicle according to an exemplary embodiment of the present disclosure.

Referring to FIG. 4 , the control method of the vehicle braking system may largely include six processes.

First, it is determined whether a failure occurs in some of the components of the main moving unit 120 (S410). When the main motor 120 determines that an abnormality has occurred in a part of the configuration of the main motor 120 , when the main motor 120 does not exert the braking ability as much as the deceleration equal to or greater than a preset value, or the main motor 120 ) is determined to be a case in which a failure occurs in the main moving unit 120, such as when the function is lost to the extent that the ABS and ESC functions cannot be exhibited. If a failure does not occur in the main moving unit 120, the redundancy control is terminated.

When it is determined that a failure has occurred in the main braking unit 120, the main driving unit 120 notifies the auxiliary braking unit 130 of the failure using a digital signal (S420). The digital signal is a high and low signal, and when a failure of the main braking unit 120 occurs, for example, a low signal is transmitted to the auxiliary braking unit 130 . The auxiliary braking unit 130 only knows the presence or absence of a failure of the main driving unit 120 only with the digital signal, and cannot know the exact cause of the failure of the main driving unit 120 .

The auxiliary braking unit 130 prepares in advance to distribute the braking force to each wheel of the vehicle (S430). The time when the auxiliary braking unit 130 receives the cause of failure through the communication unit 150 and starts generating wheel hydraulic pressure is 20 ms after the main braking unit 120 fails. However, the auxiliary braking unit 130 receives a failure signal in a short time within 1 ms through the signal bus 140 directly connected by wire between the main braking unit 120 and the auxiliary braking unit 130, so that it can be prepared in advance. have.

The main driving unit 120 transmits a signal related to the failure cause information of the main driving unit 120 to the auxiliary braking unit 130 through the communication unit 150 (S440). Based on the information transmitted through the communication unit 150, it is determined whether the main moving unit 120 can exhibit a normal braking function due to an abnormality in the main moving unit 120 (S450). If it is determined that the main braking unit 120 does not lose the braking function, the auxiliary braking unit 130 cancels the preliminary preparation and ends the control (S451).

When it is determined that the main driving unit 120 has lost the braking function, the auxiliary braking unit 130 receives the control right for braking force distribution from the main driving unit 120 . That is, the auxiliary braking unit 130 controls the braking device.

With such a control method of the vehicle braking system, the backup time of the auxiliary braking unit 130 is advanced, thereby exhibiting a backup function with better effect than the prior art. When the embodiment of the present invention is applied to an autonomous vehicle, in particular, braking redundancy can be improved, so that the safety of the occupant can be improved.

The above description is merely illustrative of the technical idea of this embodiment, and various modifications and variations will be possible by those skilled in the art to which this embodiment belongs without departing from the essential characteristics of the present embodiment. Accordingly, the present embodiments are intended to explain rather than limit the technical spirit of the present embodiment, and the scope of the technical spirit of the present embodiment is not limited by these embodiments. The protection scope of this embodiment should be interpreted by the following claims, and all technical ideas within the equivalent range should be interpreted as being included in the scope of the present embodiment.

110: master cylinder 120: main body 130: auxiliary brake unit
140: signal bus 150: communication unit 160: first euro
170: second euro 180a: front wheel 180b: rear wheel

Claims (12)

a main brake system arranged to distribute a braking force to each wheel of the vehicle;
an auxiliary brake system disposed to operate in place of the main engine when a failure occurs in the main engine;
a signal bus disposed between the main driving unit and the auxiliary braking unit and including one or more wired devices configured to transmit a signal regarding whether or not there is a mutual failure between the main driving unit and the auxiliary braking unit; and
and a communication unit arranged to transmit and receive information regarding the mutual driving state of the main driving unit and the auxiliary braking unit;
When the auxiliary brake unit detects a failure signal of the main brake unit through the signal bus, the auxiliary brake unit prepares prior to applying a braking force to each wheel of the vehicle. . The method of claim 1,
If a failure occurs in the main body,
When the main driving unit cannot distribute braking force for exerting deceleration greater than or equal to a preset value to each wheel of the vehicle, and the main driving unit is ABS (Anti-lock Brake System) or ESC (Electronic Stability Control) ), a vehicle brake system, characterized in that it is any one of the cases in which it cannot be operated. The method of claim 1,
The subject dong is,
comprising a hydraulic pump, an electric motor arranged to drive the hydraulic pump, a hydraulic module arranged to distribute hydraulic pressure to each wheel of the vehicle, and a control unit vehicle brake system. 4. The method of claim 3,
The failure of the main driving unit is a case in which a malfunction occurs in at least one of the electric motor, the hydraulic module, and the control unit. The method of claim 1,
The subject dong is,
Including a motor, a motor current sensor (MCS), a motor position sensor (MPS), a valve relay, a hydraulic circuit, a source voltage and a main controller unit (Main Controller Unit),
The failure of the main driving unit is a case in which a failure occurs in at least one of the motor, the MCS, the valve relay, the hydraulic circuit, the power supply voltage, and the main control unit. The method of claim 1,
The auxiliary braking unit,
When the auxiliary braking unit receives the information on the cause of the failure of the main driving unit through the communication unit, the auxiliary braking unit distributes braking force to each wheel of the vehicle instead of the main driving unit. The method of claim 1,
The pre-preparation is a vehicle braking system, characterized in that the auxiliary braking unit supplements oil so that the auxiliary braking unit generates hydraulic pressure. The method of claim 1,
The auxiliary braking unit distributes braking force to at least one of a front wheel and a rear wheel of the vehicle. The method of claim 1,
The signal transmitted through the signal bus includes a first signal and a second signal,
The main braking unit transmits a first signal to the auxiliary braking unit when the main driving unit operates normally and a second signal when an abnormal operation occurs. The method of claim 1,
The communication unit,
The brake system for a vehicle, characterized in that the main braking unit is arranged to transmit the cause of its failure to the auxiliary braking unit. detecting, by the control unit of the main moving unit, the occurrence of a failure of the main moving unit;
when it is determined that a failure has occurred in the main dynamic unit, transmitting the failure fact to the auxiliary braking unit using a digital signal;
a process of preparing the auxiliary braking unit in advance to distribute braking force to each wheel of the vehicle after receiving the digital signal;
transmitting failure cause information of the main braking unit to the auxiliary braking unit;
When it is determined that the main engine has lost its braking function, the auxiliary braking unit receives the control right for the distribution of braking force from the main engine
A control method of a vehicle braking system comprising a. 12. The method of claim 11,
and distributing a braking force to each wheel of the vehicle on behalf of the main driving unit after the auxiliary braking unit receives the cause of the failure information from the main driving unit.

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